Some of the most promising leads for powerful therapeutic agents have arisen from marine sponges. Aside from providing an environmentally friendly avenue to these compounds, chemical synthesis enables the development of analogs with improved bioactivity and regularly leads to fundamental discoveries in chemistry, biology and medicine. The pyrrole-imidazole alkaloids are a diverse family of marine sponge derived natural products with reported bioactivity including: anticancer, antibiotic, antiviral, antihistiminic, antimuscarinic and potential leads for cystic fibrosis and Alzheimer's disease. This proposal encompasses both the chemical and biological aspects of several members of this natural product class, including its most complex members. Thus, enantioselective syntheses of sceptrin, oxysceptrin, nakamuric acid, ageliferin, nagelamide, axinellamine, massadine, and palau'amine are proposed. The overall aim is to provide useful amounts of these natural products using concise synthetic sequences and biomimetic cascade reactions. Upon achieving practical syntheses of these compounds we will study their structure activity relationships and mechanism of action through collaborations. The biological studies will be carried out in collaboration with leaders in the fields of cancer (Professor Bob Abraham, Burnham Institute), viral (Professor Raymond Schinazi, Emory), neuropharmacology (Professor George Siggins, Scripps) and physiology (Dr. Lee Sweeny, Penn State Med. Center).